1. Technical Field
The present invention relates to a liquid ejecting apparatus which includes a liquid ejecting head having nozzles and ejecting liquid from the nozzles onto a liquid-ejected medium on the basis of liquid ejection data, and a carriage carrying the liquid ejecting head and moving in the width direction of the liquid-ejected medium which is transported, and to a liquid ejecting method in the liquid ejecting apparatus.
In this application, in the liquid ejecting apparatus, recording apparatuses such as ink jet printers, line printers, photocopiers, and facsimiles shall be included. Here, in the line printer, for example, printers shall be included each of which has a configuration in which rows of nozzles are provided to extend in a transportation direction of paper and a carriage having a recording head moves several times in the width direction of the paper when carrying out recording.
2. Related Art
In the past, as shown in JP-A-2005-319635, a configuration has been made such that, in the n-th movement of a carriage, a stop position of the carriage is determined in consideration of recording data that is one example of liquid ejection data in the next (n+1)th movement of the carriage. Accordingly, it has been possible to minimize the loss of moving distance and the loss of moving time of the carriage when ink is not discharged. As a result, it has been possible to shorten a so-called throughput that is the required time from the start of the recording to the end of the recording for each sheet of paper.
However, in accordance with the type of liquid-ejected medium (paper), powdery material is sometimes easily generated in aside end thereof. Then, if a stop position of the carriage is always determined in consideration of the recording data in the next movement, the (n+1)th time, of the carriage and recording is then carried out, there is a concern that an amount of the powdery material adhering to a nozzle becomes larger, as will be described later. Accordingly, there is a concern that the desired liquid ejection quality (recording quality) cannot be obtained.
FIGS. 7A to 7C show diagrams showing adhesion amounts of the powdery material in the faces of recording heads 51 which are shown according to the stop positions of a carriage 50 which is considered by the invention. Of these, FIG. 7A is a schematic plan view showing a relationship between a row of nozzles of the recording head 51 and a side end (59 or 60) of paper 58.
Also, although two recording heads 51 are shown, in practice, the number of recording heads 51 is not two. This is for showing the positions of the respective recording head 51, and in practice, the number of recording heads 51 is one.
Also, FIG. 7B is a diagram showing the quantity of the powdery material on a face of the recording head 51 which has stopped at a position where the left side end 59 of the paper 58 in FIG. 7A and the space between the rows of nozzles face each other. Meanwhile, the vertical axis represents the quantity of the powdery material. On the other hand, the horizontal axis represents a position in a width direction on a face of the recording head 51. Further, FIG. 7C is a diagram showing the quantity of the powdery material on a face of the recording head 51 which has stopped at a position where the middle of the paper 58 in FIG. 7A and the rows of nozzles face each other. The vertical axis and the horizontal axis are the same as those in FIG. 7B.
As shown in FIG. 7A, the recording head 51 is held by the carriage 50 and is provided so as to be able to move in a width direction with respect to a feed direction of the paper 58. Also, a total of six rows of nozzles (52 to 57), an A row to an F row in order from the left side, are formed in the recording head 51.
For example, as shown in FIG. 7A, the paper 58 is sent to the downstream side in the feed direction in a state where the recording head 51 has stopped at a position which is in a relationship such that the left side end 59 of the paper 58 and the space between the C row of nozzles 54 and the D row of nozzles 55 of the recording head 51 face each other. FIG. 7B shows an amount of the powdery material adhering to a face of the recording head 51 in such a case.
Also, the paper 58 is sent to the downstream side in the feed direction in a state where the recording head 51 has stopped at a position which is in a relationship such that the middle of the paper 58 and the A row of nozzles 51 to the F row of nozzles 57 of the recording head 51 face each other. FIG. 7C shows an amount of the powdery material adhering to a face of the recording head 51 in such a case.
As shown in FIG. 7B, the adhesion amount of the powdery material such as paper dust in the space between the C row of nozzles 54 and the D row of nozzles 55, which faces the left side end 59 of the paper 58, is significantly large.
This is considered to be because slight vibrations are generated due to the transporting of the paper 58, whereby paper dust is generated in the side end of the paper 58, and the generated paper dust is scattered up, thereby adhering to a face of the recording head 51. Also, the manner of distribution of the adhesion amount of the powdery material is considered to be close to a Gaussian distribution.
Also, as shown in FIG. 7C, the adhesion amount of the powdery material in the recording head 51 which faces the middle of the paper 58 is very small compared to the case of FIG. 7B. This is considered to be because the powdery material such as paper dust is not easily generated in the middle of the paper 58, so that the adhesion amount to a face of the recording head 51 is small.
Also, a case where the paper 58 is sent to the downstream side in the feed direction in a state where the recording head 51 has stopped at a position which is in a relationship such that the right side end 60 of the paper 58 and the nozzle face of the recording head 51 face each other is the same as the case of a position which is in a relationship such that the left side end 59 and the nozzle face of the recording head 51 face each other. That is, there is a peak of distribution of the adhesion amount at a position which faces the side end. Since an amount and distribution of the powdery material adhering to a face of the recording head 51 are the same as those in FIG. 7B, illustration of the distribution is omitted.
From these points, it is considered that slight vibrations are generated due to the sending of the paper 58, whereby paper dust is generated in the side ends (59 and 60) of the paper 58, and the generated paper dust is scattered up, thereby adhering to a face of the recording head 51.
Then, if a stop position of the carriage 50 is determined in consideration of the liquid ejection data in the next movement (the (n+1) th time) of the carriage 50, as described above, regardless of the liquid ejection setting and liquid ejection is then carried out, there is a concern that an amount of the powdery material adhering to the nozzle becomes larger. Accordingly, there is a concern that desired liquid ejection quality cannot be obtained.